Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24253
Jeffrey J. Murphy, C. Shaddix
Researchers at Sandia National Laboratories have been investigating large-scale pool fires, both experimentally and numerically, for several years, because of the risk that these fires pose to critical engineered systems during transport accident scenarios [1]. In addition, Sandia recently implemented an insulated, water-cooled fiber optic probe that used a combined HeNe-laser-absorption, 2-color emission technique to determine soot volume fraction distributions and soot temperatures over a 2-cm sampling distance within 5-m diameter JP-8 pool fires [2].
{"title":"Transient Measurements of Gas Species Concentrations and Soot Properties in Pool Fires","authors":"Jeffrey J. Murphy, C. Shaddix","doi":"10.1115/imece2001/htd-24253","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24253","url":null,"abstract":"\u0000 Researchers at Sandia National Laboratories have been investigating large-scale pool fires, both experimentally and numerically, for several years, because of the risk that these fires pose to critical engineered systems during transport accident scenarios [1]. In addition, Sandia recently implemented an insulated, water-cooled fiber optic probe that used a combined HeNe-laser-absorption, 2-color emission technique to determine soot volume fraction distributions and soot temperatures over a 2-cm sampling distance within 5-m diameter JP-8 pool fires [2].","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122577521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The hot-electron blasting model is extended in this work to describe the ultrafast deformation in thin metal films in the sub-picosecond to picosecond domain. The driving force depends on both the temperature and temperature gradient in the hot electron gas, while the metal lattices remain thermally undisturbed in this highly non-equilibrium regime. The dominating parameters characterizing the ultrafast deformation are identified. The phonon-electron interaction model is used to describe the electron temperature, while renormalization of elastic moduli is accommodated in the dynamic equation of motion. Method of lines is used to solve the nonlinearly coupled equations describing ultrafast deformation in the sub-picosecond domain.
{"title":"Ultrafast Deformation in Femtosecond Laser Heating","authors":"D. Tzou, J. Beraun, J. K. Chen","doi":"10.1115/1.1447934","DOIUrl":"https://doi.org/10.1115/1.1447934","url":null,"abstract":"\u0000 The hot-electron blasting model is extended in this work to describe the ultrafast deformation in thin metal films in the sub-picosecond to picosecond domain. The driving force depends on both the temperature and temperature gradient in the hot electron gas, while the metal lattices remain thermally undisturbed in this highly non-equilibrium regime. The dominating parameters characterizing the ultrafast deformation are identified. The phonon-electron interaction model is used to describe the electron temperature, while renormalization of elastic moduli is accommodated in the dynamic equation of motion. Method of lines is used to solve the nonlinearly coupled equations describing ultrafast deformation in the sub-picosecond domain.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125532278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24276
J. Foley, C. Avedisian
In this paper we extend the theory of photothermal deflection spectroscopy for an isotropic film-on-substrate system to include the thermal contact resistance between the two materials and absorption of energy in the film and substrate. The model is formulated as a three-domain system (gas, film and substrate) with coupling conditions at the various interfaces, including a thermal contact resistance. Closed form expressions are obtained for the temperatures in each domain. The analysis for probe beam deflection is confirmed by comparison to well-known limits of infinite film thickness, zero film thickness, zero contact resistance, and a thin absorbing layer at the surface of the film. The formulations are tested against NIST standard reference materials (SRM) using numerically generated beam deflection data to extract thermal diffusivity of a bulk material, and of two SRMs pressed together to extract thermal contact resistance. The results show the feasibility of using to determine the thermal contact resistance of a layered sample from beam deflection data.
{"title":"The Feasibility of Using Photothermal Deflection Spectroscopy to Measure Thermal Contact Resistance in a Film on Substrate System","authors":"J. Foley, C. Avedisian","doi":"10.1115/imece2001/htd-24276","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24276","url":null,"abstract":"\u0000 In this paper we extend the theory of photothermal deflection spectroscopy for an isotropic film-on-substrate system to include the thermal contact resistance between the two materials and absorption of energy in the film and substrate. The model is formulated as a three-domain system (gas, film and substrate) with coupling conditions at the various interfaces, including a thermal contact resistance. Closed form expressions are obtained for the temperatures in each domain.\u0000 The analysis for probe beam deflection is confirmed by comparison to well-known limits of infinite film thickness, zero film thickness, zero contact resistance, and a thin absorbing layer at the surface of the film. The formulations are tested against NIST standard reference materials (SRM) using numerically generated beam deflection data to extract thermal diffusivity of a bulk material, and of two SRMs pressed together to extract thermal contact resistance. The results show the feasibility of using to determine the thermal contact resistance of a layered sample from beam deflection data.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129504649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24282
Yasir M. Shariff, T. S. Ravigururajan
The paper presents results from an experimental study on refrigerant mixture flow (R-407C) in which the heat transfer coefficient was measured across a range of heat and mass fluxes. Flow characteristics in smooth horizontal mesochannels were measured for two different conditions, 1) subcooled and 2) saturated boiling with diameters of 1.59, 2.78, and 3.97 mm and a length of 50.8 mm in refrigerant mixture (R-407C). Experiments were performed at heat fluxes of 2 and 11 kW/m2 for the subcooled boiling and 15 and 29 kW/m2 for the saturated boiling. The mass flux was varied from 0.45 to 1.55 kg/min and the refrigerant was subcooled to 8°C. The saturated boiling experiments were conducted for ΔTsat = 0 to 27°C. The heat transfer coefficients were found to be dependent on channel size, heat flux, and mass flux variations. For smaller channel diameters, the heat transfer rate significantly increased as compared to larger channel diameters. The results showed an increase of 100% in heat transfer coefficient when compared to traditional and micro-channel boiling characteristics.
{"title":"Two-Phase Refrigerant Mixture (R-407C) Flow in Smooth Meso-Scale Heat Exchangers","authors":"Yasir M. Shariff, T. S. Ravigururajan","doi":"10.1115/imece2001/htd-24282","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24282","url":null,"abstract":"\u0000 The paper presents results from an experimental study on refrigerant mixture flow (R-407C) in which the heat transfer coefficient was measured across a range of heat and mass fluxes. Flow characteristics in smooth horizontal mesochannels were measured for two different conditions, 1) subcooled and 2) saturated boiling with diameters of 1.59, 2.78, and 3.97 mm and a length of 50.8 mm in refrigerant mixture (R-407C). Experiments were performed at heat fluxes of 2 and 11 kW/m2 for the subcooled boiling and 15 and 29 kW/m2 for the saturated boiling. The mass flux was varied from 0.45 to 1.55 kg/min and the refrigerant was subcooled to 8°C. The saturated boiling experiments were conducted for ΔTsat = 0 to 27°C. The heat transfer coefficients were found to be dependent on channel size, heat flux, and mass flux variations. For smaller channel diameters, the heat transfer rate significantly increased as compared to larger channel diameters. The results showed an increase of 100% in heat transfer coefficient when compared to traditional and micro-channel boiling characteristics.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133060682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24238
G. Su, J. Quintiere, N. Schultz
The objective of the project is to develop water mist extinguishments design by scaling. The report describes the requirement and criteria of scaling fire, scale model, and the results of suppression for a developing water mist system design. The Maritime Safety Committee Draft Circular, MSC 914 is used as a basis test to evaluate a water mist design. A series of three full-scale tests related to MSC 914 were performed: fire only, fire with steel trailers, and fire with steel trailers and combustible commodities. A simulation was accordingly studied. Then, a scaled water mist design was tested in the scale model to find the characteristics needed for suppression in terms of pressure, water flow rate, droplet size, and the spray momentum. Based on these characteristics, a candidate nozzle will be selected for the full-scale MSC 914 test. The results so far show that the water mist system can effectively suppress the fire in scaled MSC 914 model. The full-scale MSC 914 is scheduled for September 2001. Therefore, the final answer is still pending until then. Scaling results are confirmed for temperatures, heat flux and flow for the MSC 914 fire without water add in.
{"title":"Physical Scaling of Fire Suppression by Water Mist","authors":"G. Su, J. Quintiere, N. Schultz","doi":"10.1115/imece2001/htd-24238","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24238","url":null,"abstract":"\u0000 The objective of the project is to develop water mist extinguishments design by scaling. The report describes the requirement and criteria of scaling fire, scale model, and the results of suppression for a developing water mist system design. The Maritime Safety Committee Draft Circular, MSC 914 is used as a basis test to evaluate a water mist design. A series of three full-scale tests related to MSC 914 were performed: fire only, fire with steel trailers, and fire with steel trailers and combustible commodities. A simulation was accordingly studied. Then, a scaled water mist design was tested in the scale model to find the characteristics needed for suppression in terms of pressure, water flow rate, droplet size, and the spray momentum. Based on these characteristics, a candidate nozzle will be selected for the full-scale MSC 914 test. The results so far show that the water mist system can effectively suppress the fire in scaled MSC 914 model. The full-scale MSC 914 is scheduled for September 2001. Therefore, the final answer is still pending until then. Scaling results are confirmed for temperatures, heat flux and flow for the MSC 914 fire without water add in.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133866480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24265
Zhixiong Guo, Sunil Kumar, S. Maruyama
In this study transient radiative heat transfer is investigated in scattering, absorbing, and emitting media. The radiation element method is formulated for the first time to solve the transient radiative transfer equation in 3-D geometries. The sensitivity and accuracy of the method are examined. A good agreement of temporal transmittance predicted by the present method and Monte Carlo method is found. The characteristics of transient analysis are investigated via various problems of radiative transfer in inhomogeneous cubes. It is found that the transmitted signals are strongly affected by the inhomogeneous properties of the media through which the radiation has passed. In the position where the radiation travels a larger optical thickness, the broadening of the transmitted pulse width is more obvious and the magnitude of the transmittance is smaller.
{"title":"Transient Radiation Element Method for Three-Dimensional Scattering, Absorbing, and Emitting Media","authors":"Zhixiong Guo, Sunil Kumar, S. Maruyama","doi":"10.1115/imece2001/htd-24265","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24265","url":null,"abstract":"\u0000 In this study transient radiative heat transfer is investigated in scattering, absorbing, and emitting media. The radiation element method is formulated for the first time to solve the transient radiative transfer equation in 3-D geometries. The sensitivity and accuracy of the method are examined. A good agreement of temporal transmittance predicted by the present method and Monte Carlo method is found. The characteristics of transient analysis are investigated via various problems of radiative transfer in inhomogeneous cubes. It is found that the transmitted signals are strongly affected by the inhomogeneous properties of the media through which the radiation has passed. In the position where the radiation travels a larger optical thickness, the broadening of the transmitted pulse width is more obvious and the magnitude of the transmittance is smaller.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122032093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24256
Kapil Singh, S. Frankel, J. Gore
The noise generated by the standard Sandia Non-premixed Turbulent Flame Workshop (TNF) DLR-A and DLR-B flames was experimentally studied and compared with the noise generated by a cold air jet from same burner with identical exit Reynolds Numbers (Re). The axial and radial variations were studied for both reacting and non-reacting jets and compared.
{"title":"A Study of Effects of Combustion on the Noise Generated by a Circular Jet Flow","authors":"Kapil Singh, S. Frankel, J. Gore","doi":"10.1115/imece2001/htd-24256","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24256","url":null,"abstract":"\u0000 The noise generated by the standard Sandia Non-premixed Turbulent Flame Workshop (TNF) DLR-A and DLR-B flames was experimentally studied and compared with the noise generated by a cold air jet from same burner with identical exit Reynolds Numbers (Re). The axial and radial variations were studied for both reacting and non-reacting jets and compared.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"462 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125813992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24273
Lixin You, Hongtan Liu
A two-dimensional, two-phase and multi-component flow and transport model has been developed to simulate the flow and transport phenomena in the cathodes of PEM fuel cells. First, the governing equations based on a “two-phase mixture model” are derived by using a unified approach that describes the flow and transport in the gas channel and gas diffuser simultaneously. Then, the detailed boundary conditions are discussed especially at the gas diffuser/catalyst layer interface, which couples the flow, transport, potential and current density in the anode, the catalyst layer and membrane. Next, the model is validated by comparing the modeling results with experimental data. Further, typical distributions of oxygen and water-mass fraction in the “two-phase mixture,” as well as water vapor mass fraction, liquid saturation and liquid velocity vector are presented. Finally, the model is used to study the influences of two of the most critical issues of PEM fuel cell operation: i.e., the water and the thermal management on the two-phase flow. It was found that the two-phase flow characteristics in the cathode depend on some of the following factors: current density, operating temperature, and cathode and anode humidification temperatures. The dependence of the formation and the distribution of the two-phase flow in the gas diffuser and gas channel on these factors is explored. By studying the effects of these parameters on the two-phase flow and the fuel cell performance, the model can be used to study a water and thermal management scheme.
{"title":"A Two-Phase and Multi-Component Model for the Cathode of PEM Fuel Cells","authors":"Lixin You, Hongtan Liu","doi":"10.1115/imece2001/htd-24273","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24273","url":null,"abstract":"\u0000 A two-dimensional, two-phase and multi-component flow and transport model has been developed to simulate the flow and transport phenomena in the cathodes of PEM fuel cells. First, the governing equations based on a “two-phase mixture model” are derived by using a unified approach that describes the flow and transport in the gas channel and gas diffuser simultaneously. Then, the detailed boundary conditions are discussed especially at the gas diffuser/catalyst layer interface, which couples the flow, transport, potential and current density in the anode, the catalyst layer and membrane. Next, the model is validated by comparing the modeling results with experimental data. Further, typical distributions of oxygen and water-mass fraction in the “two-phase mixture,” as well as water vapor mass fraction, liquid saturation and liquid velocity vector are presented. Finally, the model is used to study the influences of two of the most critical issues of PEM fuel cell operation: i.e., the water and the thermal management on the two-phase flow. It was found that the two-phase flow characteristics in the cathode depend on some of the following factors: current density, operating temperature, and cathode and anode humidification temperatures. The dependence of the formation and the distribution of the two-phase flow in the gas diffuser and gas channel on these factors is explored. By studying the effects of these parameters on the two-phase flow and the fuel cell performance, the model can be used to study a water and thermal management scheme.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125369671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24249
P. DesJardin, S. Tieszen, T. O'Hern
Measurements of a large, 1-m in diameter, turbulent buoyant methane-air fire plume are taken and compared to results from numerical simulation using Large Eddy Simulation (LES). The experiments are carried out in Sandia’s FLAME (Fire Laboratory for Accreditation of Models and Experiments) facility and consist of a low velocity (0.12 m/sec) methane plume emitting upwards into ambient air. Numerical results show evidence of strong entrainment velocities resulting in flame pinch off near the base of the plume. Preliminary comparisons of the LES results to experimental measurements show good qualitative agreement to mean stream-wise and cross-stream velocities.
{"title":"Large Eddy Simulation and Experimental Measurements of a Methane-Air Fire Plume","authors":"P. DesJardin, S. Tieszen, T. O'Hern","doi":"10.1115/imece2001/htd-24249","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24249","url":null,"abstract":"\u0000 Measurements of a large, 1-m in diameter, turbulent buoyant methane-air fire plume are taken and compared to results from numerical simulation using Large Eddy Simulation (LES). The experiments are carried out in Sandia’s FLAME (Fire Laboratory for Accreditation of Models and Experiments) facility and consist of a low velocity (0.12 m/sec) methane plume emitting upwards into ambient air. Numerical results show evidence of strong entrainment velocities resulting in flame pinch off near the base of the plume. Preliminary comparisons of the LES results to experimental measurements show good qualitative agreement to mean stream-wise and cross-stream velocities.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123580384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/htd-24281
A. Devpura, R. Prasher, P. Phelan
Solid-solid thermal boundary resistance (Rb) plays an important role in determining the heat flow between materials. The acoustic mismatch model (AMM) and the diffuse mismatch model (DMM), work pretty well in describing and predicting the thermal energy transport at solid-solid interface at very low temperatures (in the range of few Kelvin). At moderate cryogenic temperatures they do not perform that well, and the reason may be attributed to the dominance of scattering in determining Rb. Scattering mediated acoustic mismatch model (SMAMM) was developed on this principle. Though SMAMM works well, it has some fundamental problems. SMAMM’s assumption of U-processes, for amorphous layer formed between materials, is physically unexplainable. It also assumes unrealistically small scattering time. We propose a modified version of SMAMM called Amorphous SMAMM, which takes into account amorphous material properties for the interstitial layer formed, to find the scattering time to be used in SMAMM. This model performs better than all the models in the range of 25 to 60 K in predicting Rb. Above this temperature, original SMAMM performs better, but Amorphous SMAMM always performs better than the AMM. Amorphous SMAMM does not run into any physical problems with the assumptions made, hence the results have a better physical significance than SMAMM’s.
{"title":"Using Amorphous Material Properties in Scattering-Mediated Acoustic Mismatch Model for Predicting Thermal Boundary Resistance","authors":"A. Devpura, R. Prasher, P. Phelan","doi":"10.1115/imece2001/htd-24281","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24281","url":null,"abstract":"\u0000 Solid-solid thermal boundary resistance (Rb) plays an important role in determining the heat flow between materials. The acoustic mismatch model (AMM) and the diffuse mismatch model (DMM), work pretty well in describing and predicting the thermal energy transport at solid-solid interface at very low temperatures (in the range of few Kelvin). At moderate cryogenic temperatures they do not perform that well, and the reason may be attributed to the dominance of scattering in determining Rb. Scattering mediated acoustic mismatch model (SMAMM) was developed on this principle. Though SMAMM works well, it has some fundamental problems. SMAMM’s assumption of U-processes, for amorphous layer formed between materials, is physically unexplainable. It also assumes unrealistically small scattering time. We propose a modified version of SMAMM called Amorphous SMAMM, which takes into account amorphous material properties for the interstitial layer formed, to find the scattering time to be used in SMAMM. This model performs better than all the models in the range of 25 to 60 K in predicting Rb. Above this temperature, original SMAMM performs better, but Amorphous SMAMM always performs better than the AMM. Amorphous SMAMM does not run into any physical problems with the assumptions made, hence the results have a better physical significance than SMAMM’s.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133857693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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